1. Field of the Invention
The present invention relates to the field of switching DC to DC converters.
2. Prior Art
DC to DC switching converters of various types are well known in the prior art. Such converters may be used to convert one DC voltage to a second DC voltage which, depending on the converter, may be higher or lower than the first voltage. Switching converters provide a voltage step-up capability not found in linear regulators, and offer higher efficiency than linear regulators in most voltage step-down applications, particularly where the output voltage of the converter is substantially less than the input voltage to the converter. However, switching converters of usual design tend to create significant electrical noise in the form of current ripple on both the converter input and the converter output. This requires substantial capacitance coupled to the input and to the output to keep the voltage ripple on the input supply and on the output voltage within the desired tolerances. While switching converter controllers are generally integrated devices, preferably with limited external devices needed for the complete controller, relatively large filter capacitors on the converter input and output only increases converter cost and board space required for the operative converter.
The present invention, among other things, provides a way of substantially reducing the input ripple and the output ripple in a DC to DC switching converter.
Ripple canceling, soft switching isolated DC/DC converters with reduced voltage stress synchronous rectification. The converters include interleaved switching converters providing power to a node supplying power to a zero volt switching bi-phase power conversion stage driving synchronous rectifiers feeding an output filter. In one embodiment, the interleaved converters are boost mode converters operating in continuous conduction mode boost converters. Various embodiments are disclosed.